6 timeless articles about learning Elm

Learning Elm? When I started learning it in 2016, Joël Quenneville’s technical writing was a huge resource—and it still is.

Joël’s clear, well-reasoned writing explains how to solve common issues and leverage Elm’s type system.

Here are 6 timeless articles from Elm’s “Coach Q”:

✅ Booleans and Enums


If you come from languages that don’t have union types, it’s natural to reach for the familiar Bool and String types to model your data.

In Elm, we can do better! Joël uses concrete, clear examples to show us how.

⚙️ Maybe Mechanics


Elm makes certain bugs impossible by making you declare a nullable value explicitly.

But knowing when and how to use the Maybe type is its own skill. Joël explains clearly what to do in the most common situations.

⚖️ Problem Solving with Maybe


Maybe is useful, but using it for each instance of a nullable value can overwhelm your codebase.

Joël shows how to make maintenance easier and how to model for more clarity.

😵‍💫 What’s Weird with Maybe List


Combining Maybe with types that have their own null states can make your program states ambiguous.

Joël provides helpful alternatives and makes a case for when Maybe (List a) is useful.

🎲 Rolling Random Romans


Generating random values in Elm is a challenging beginner topic. How do you produce random values when all functions are pure?

Joël helps introduce the Generator type and breaks the problem down into simple steps.

🪲 Debugging DOM event handlers in Elm


Elm’s helpful constraints make web development easier. But debugging the boundary between JavaScript and Elm (e.g. decoding JSON values) can be confusing.

Joël shares helpful tips for “seeing into” decoders.

This post was originally a Twitter thread as part of Ship 30 for 30.